Process for increasing radiation-curability of a radiation-curable resin

Abstract

Radiation-curing reaction of a radiation-curable resin such as an unsaturated polyester resin is promoted by using a combination of an ionizing radiation and a substantial amount of an adding material.

We claim: 
     
       1. A process for curing an unsaturated polyester resin comprising the steps of: incorporating in said unsaturated polyester resin from about 50 to about 300 parts by weight, per 100 parts by weight of the resin, of one or more compounds of a finely powdered material of an inactive inorganic compound selected from the group consisting of calcium carbonate, clay, quartz powder, gypsum, cement, mica powder, glass powder, diatomaceous earth, talc, asbestos and red mud of bauxite; and   irradiating the resin containing the compounds with an ionizing radiation applied thereto at a dose rate of 10 -   2  - 2 X 10 7  rad/sec for a total dose of 0.1-10 Mrad, and at a starting temperature of from about -20°C to about 60°C,   whereby secondary radiation being emitted from the compounds and/or the compounds activating themselves promote the radiation-curing reaction.   
     
     
       2. A process in accordance with claim 1, in which said incorporating step further includes incorporating a basic salt of a metal belonging to Group I or II of the Periodic Table in an amount of 0.1 - 50 parts by weight per 100 parts by weight of said resin. 
     
     
       3. A process in accordance with claim 1 in which said ionizing radiation is a member selected from the group consisting of α-ray, β-ray, γ-ray, X-ray, electron beam and the mixtures thereof. 
     
     
       4. A process in accordance with claim 1 in which said inorganic compound is calcium carbonate and said ionizing radiation is an accelerated electron beam or γ-ray. 
     
     
       5. A process in accordance with claim 2 in which said compound is a combination of calcium carbonate and magnesium oxide and said ionizing radiation is an electron beam.